Electric compressor

ABSTRACT

An electric compressor includes a compression part, a motor that drives the compression part, a cylindrical housing that accommodates therein the compression part and the motor, a supporting member, and a first vibration damper. The supporting member supports the housing and is configured to be fixed to a target to which the compressor is attached. The first vibration damper is disposed between the housing and the supporting member so as to keep the housing free from contact with the supporting member and the target. The first vibration damper has therein a hollow enclosed space.

BACKGROUND OF THE INVENTION

The present invention relates to an electric compressor.

Japanese Unexamined Patent Application Publication No. 2013-224652 discloses a cylindrical electric compressor adapted for use in a vehicle air conditioner. The electric compressor includes a housing, two supporting members, and a vibration damper. The housing has therein a motor and a compression part that is driven by the motor. The supporting members are formed in a semi-cylindrical shape and support the housing by holding the housing on the periphery thereof. The supporting members are fixed to any part or target in the engine compartment of the vehicle (e.g. a vehicle frame or the engine). In other words, the housing is fixed to the target via the supporting members. The vibration damper is disposed between each of the supporting members and the housing so that the supporting members and the housing are not in direct contact with each other.

According to the configuration of the electric compressor disclosed in Japanese Unexamined Patent Application Publication No. 2013-224652, the vibration damper prevents transmission of vibration from the compression part and the motor in the electric compressor to the engine. However, the vibration damper used in the electric compressor disclosed in the Publication is formed of a solid rubber. Heat is generated relatively easily in such solid rubber due to vibration and, therefore, the durability of the heated vibration damper is lowered, which may lead to poor vibration damping property.

The present invention is directed to providing an electric compressor that prevents the transmission of vibration from the housing to the target to which the housing of the compressed is attached.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, there is provided an electric compressor that includes a compression part, a motor that drives the compression part, a cylindrical housing that accommodates therein the compression part and the motor, a supporting member, and a first vibration damper. The supporting member supports the housing and is configured to be fixed to a target to which the compressor is attached. The first vibration damper is disposed between the housing and the supporting member. The first vibration damper keeps the housing free from contact with the supporting member and the target. The first vibration damper has therein a hollow enclosed space.

In an electric compressor according to an aspect of the present invention, the first vibration damper is disposed between the housing and the supporting member so as to keep the housing free from contact with the supporting member and, therefore, the first vibration damper prevents transmission of vibration of the housing to the target through the supporting member. The housing and the target are not in contact with each other, so that direct transmission of the vibration from the housing to the target is prevented. The first vibration damper is formed hollow. Specifically, the first vibration damper has therein a space that is enclosed and sealed from the exterior thereof. Selecting a material for filling the hollow space of the first vibration damper that is less heat-generative under vibration than the material of the first vibration damper further prevents heat generation due to the vibration, as compared with the vibration damper that is formed solid. Therefore, the durability of the first vibration damper against the heat is improved and the transmission of vibration from the housing to the target is effectively prevented.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of an electric compressor according to a first embodiment of the present invention cut along an axis of the housing;

FIG. 2 is a transverse sectional view taken along line II-II of FIG. 1;

FIG. 3 is a longitudinal sectional view showing the electric compressor of FIG. 1 and a pair of assemblies each including a supporting member and a vibration damper that is yet to be inflated with air before being mounted to the housing of the electric compressor;

FIG. 4 is a longitudinal sectional view of the electric compressor with the paired assemblies of FIG. 3 mounted in place on the housing of the electric compressor;

FIG. 5 is a transverse sectional view of an electric compressor according to a first modification of the present invention;

FIG. 6 is a transverse sectional view of an electric compressor according to a second modification of the present invention, showing a state in which the air pressure of the vibration dampers is maintained in a specified range;

FIG. 7 is a transverse sectional view of the electric compressor according to the second modification of the present invention, showing a state in which the air pressure of one of the vibration dampers is below the specified range;

FIG. 8A is a cross-sectional view of one of the vibration dampers and the vicinity thereof, taken along line VIIIA-VIIIA of FIG. 6;

FIG. 8B is a cross-sectional view of one of the vibration dampers and the vicinity thereof, taken along line VIIIB-VIIIB of FIG. 7;

FIG. 9 is a transverse sectional view of an electric compressor according to a second embodiment of the present invention;

FIG. 10 is a transverse sectional view of an electric compressor according to a third modification of the present invention;

FIG. 11 is a transverse sectional view of an electric compressor according to a third embodiment of the present invention;

FIG. 12 is a transverse sectional view of an electric compressor according to a fourth modification of the present invention;

FIG. 13 is a transverse sectional view of an electric compressor according to a fourth embodiment of the present invention;

FIG. 14 is a transverse sectional view of an electric compressor according to a fifth modification of the present invention; and

FIG. 15 is a cross-sectional view of a vibration damper and a supporting member of an electric compressor according to a fifth embodiment of the present invention.

The following will describe major features of the embodiments described hereinafter. It is to be noted that technical elements described hereafter are all independent and exhibit a technical significance when used alone or in various combinations, and the combinations of such technical elements are not limited to those described herein.

DETAILED DESCRIPTION OF THE EMBODIMENTS First Embodiment

A first embodiment of the present invention will now be described with reference to FIGS. 1 to 4. An electric compressor, which is designated by numeral 10, is mounted to an electric vehicle or a hybrid car and adapted for use in a vehicle air conditioner. In FIG. 2, an engine to which the electric compressor 10 is mounted is designated by numeral 60, but in FIGS. 1, 3, and 4 the engine 60 is not illustrated. It is to be noted in the drawings some cross sections are not indicated by hatching and also that in FIG. 2 the internal configuration of a housing 12 is not illustrated. Referring to FIG. 1, the electric compressor 10 includes the housing 12 of a substantially cylindrical shape, a rotating shaft 39 that is rotatably supported in the housing 12, a motor including a stator coil 30 and a rotor 34 and a compression part 22. The motor (30, 34) and the compression part 22 are housed in the housing 12. The electric compressor further includes a pair of tubes 50A, 50B that extend around the periphery of the housing 12, and a pair of rims 54A, 54B (see FIG. 2) that support the housing 12. The rotating shaft 39 extends in the axial direction of the housing 12 (in the horizontal direction in FIG. 1). The motor (30, 34) is disposed on one end side the rotating shaft 39 (or the right hand side in FIG. 1), and the compression part 22 is disposed on the other end side of the rotating shaft 39. Specifically, the motor (30, 34) and the compression part 22 are arranged along the axial direction of the housing 12. The motor (30, 34) supplied with electric power drives the rotating shaft 39, which in turn drives the compression part 22. Although not shown in the drawing, the electric compressor 10 may be equipped with an inverter.

The housing 12 includes a cylindrical motor housing 16 having a closed end, a front housing 18 that is installed in the motor housing 16, and a discharge housing 20 that closes the open end of the motor housing 16 to form an end of the motor housing 16 on the left hand side in FIG. 1.

The motor housing 16 is made of a metal such as aluminum alloy. The motor housing includes 16 a peripheral wall and a bottom wall 16B. The motor housing 16 has through the peripheral wall thereof a suction port 16A. The suction port 16A is located at a position adjacent to the bottom wall 16B of the motor housing 16. A plain bearing 47 that rotatably supports one end of the rotating shaft 39 (or the right end in FIG. 1) is disposed in the bottom wall 16B of the motor housing 16.

The front housing 18 is made of a metal such as aluminum alloy. The front housing 18 installed in the motor housing 16 separates the interior of the motor housing 16 into a space in which the motor (30, 34) is disposed and a space in which the compression part 22 is disposed. A plain bearing 45 is disposed in the front housing 18 for rotatably supporting the other end of the rotating shaft 39 (or the left end in FIG. 1).

The discharge housing 20 has a cylindrical shape with a closed end and is made of a metal such as aluminum alloy. The discharge housing 20 has therethrough a discharge port 20A. With the discharge housing 20 mounted to the motor housing 16, a discharge chamber 20B is formed between the compression part 22 and the discharge housing 20. The discharge chamber 20B is communicable with the outside through the discharge port 20A.

The rotating shaft 39 is mounted in the housing 12. As described above, the rotating shaft 39 is rotatably supported at one end thereof by the plain bearing 47 provided in the motor housing 16 and at the other end thereof by the plain bearing 45 provided in the front housing 18.

The motor (30, 34) is disposed on the side of the front housing 18 that is adjacent to the bottom wall 16B in the motor housing 16 (or on the right hand side of the front housing 18 in FIG. 1). The motor (30, 34) includes a rotor 34 fixed on the rotating shaft 39 and a stator 30 that is disposed raidally outward of the rotor 34. A coil wire (not shown) is wound around teeth (not shown) of the stator 30. The motor (30, 34) is electrically connected to a drive circuit (not shown) and driven by an AC power supplied from the drive circuit.

The compression part 22 is disposed in the motor housing 16 on the open end side thereof (on the left side of the front housing 18 in FIG. 1). The compression part 22 includes a fixed scroll 26 fixed to the motor housing 16 and a movable scroll 24 disposed facing the fixed scroll 26. The fixed scroll 26 and the movable scroll 24 are engaged with each other in such a way that a compression chamber 22A is formed therebetween. The volume of the compression chamber 22A varies with the orbital motion of the movable scroll 24. The compression chamber 22A is communicable with the space of the motor housing 16 in which the motor (30, 34) is disposed and draws in refrigerant gas from the space. The compression chamber 22A is communicable with the discharge chamber 20B and discharges the compressed refrigerant gas into the discharge chamber 20B.

Referring to FIG. 2, the tubes 50A, 50B (only the tube 50A being shown in the drawing) are formed in a substantially annular shape around the periphery of the motor housing 16, respectively, and made of a rubber, such as natural rubber (NB), isoprene rubber (IR), butadiene rubber (BR), butyl rubber (IIR), ethylene propylene diene rubber (EPDM), and silicone rubber. As shown in FIGS. 1 and 2, the tubes 50A, 50B are made hollow and the interior of the respective tubes 50A, 50B is enclosed and sealed from the exterior thereof. As shown in FIG. 1, the tubes 50A, 50B are provided with valves 52A, 52B, respectively, and air is injected into and removed from the tubes 50A, 50B through the valves 52A, 52B, respectively. In FIGS. 1 and 2, the tubes 50A, 50B are inflated with an appropriate volume of air and the air pressure is maintained in a specified range. As shown in FIG. 1, the tubes 50A, 50B have in the outer periphery thereof (the radially outward surfaces of the tubes 50A, 50B) five grooves 51A, 51B, respectively, formed extending along the entire circumference of the respective annular tubes 50A, 50B. The grooves 51A, 51B are provided equidistantly in the radial direction in the cross section of the tubes 50A, 50B in FIG. 1. It is to be noted that the material of the tubes 50A, 50B is not limited to rubber, and any other materials such as αGEL (registered trademark) may be used. The tubes 50A, 50B correspond to an example of the first vibration damper of the present invention and the grooves 51A, 51B correspond to the recesses of the present invention, respectively.

The motor housing 16 has in the periphery thereof a pair of grooves 16C, 16D each extending along the entire circumference of the motor housing 16. The groove 16C is formed on the motor (30, 34) side with respect to the axial center of the housing 12, and the groove 16D on the compression part 22 side, respectively. Imaginary planes passing through the centers of the respective grooves 16C, 16D are perpendicular to the axis of the housing 12. Tubes 50A, 50B are fitted along the grooves 16C, 16D, respectively. The inner diameter of the annular-shaped tubes 50A, 50B having an internal pressure maintained within the specified range substantially correspond to the outer diameter of the motor housing 16 as measured at the bottom of the grooves 16C, 16D. The grooves 16C, 16D in the periphery of the motor housing 16 facilitate positioning of the tubes 50A, 50B. The outer diameters of the motor housing 16 measured at the positions including the grooves 16C, 16D are smaller than the outer diameter of the motor housing 16 measured at a position other than the position including the grooves 16C, 16D. Therefore, the diametric dimension of the electric compressor 10 measured at the positions where the tubes 50A, 50B are fitted is smaller, as compared with a case in which no grooves such as 16C, 16D are formed in the periphery of the motor housing 16 to receive the tubes such as 50A, 50B.

Referring to FIG. 2, the rims 54A, 54B (only the rim 54A being shown in the drawing) are formed in a substantially annular shape around the tubes 50A, 50B, respectively and made of a metal such as aluminum alloy. As shown in FIG. 1, the rims 54A, 54B are formed in a substantially arc shape. Specifically, the inner peripheries of the rims 54A, 54B are curved along the outer peripheries of the tubes 50A, 50B, respectively. The rims 54A, 54B have in the inner periphery thereof five projections 56A, 56B formed extending along the entire circumference of the respective tubes 50A, 50B. The projections 56A, 56B are spaced equidistantly in the circumferential direction in the cross section of the respective tubes 50A, 50B in FIG. 1. The interval of any two adjacent projections 56A, 56B of the rims 54A, 54B is substantially the same as the interval of any two adjacent grooves 51A, 51B of the tubes 50A, 50B, respectively. The width and the height of the projections 56A, 56B are substantially the same as the width and the depth of the grooves 51A, 51B. The inner diameters of the rims 54A, 54B are substantially the same as the outer diameter of the tubes 50A, 50B, respectively, so that the projections 56A, 56B of the rims 54A, 54B are fitted in the grooves 51A, 51B of the tubes 50A, 50B, respectively, thereby preventing the tubes 50A, 50B from being displaced from the rims 54A, 54B, respectively. The tubes 50A, 50B are disposed between the motor housing 16 and the rims 54A, 54B, respectively. When the air pressure of the tubes 50A, 50B is maintained within the specified range, the tubes 50A, 50B are in close contact with the motor housing 16 and the rims 54A, 54B, respectively. As shown in FIG. 1, because the tubes 50A, 50B are disposed between the rims 54A, 54B and the motor housing 16, the rims 54A, 54B are not in contact with the motor housing 16. It is to be noted that the rims 54A, 54B correspond to an example of the supporting member of the present invention, and the projections 56A, 56B correspond to an example of the projections of the present invention.

As shown in FIG. 1, the rims 54A, 54B have at the top and bottom thereof mountings 58A, 58B of a flat plate shape, respectively. Each of the mountings 58A, 58B has wider surfaces that are parallel to the axial direction of the housing 12. As shown in FIG. 2, the engine 60 has two mounting projections 62 projecting one above the other from a side of the engine 60. The projections 62 extend in the direction away from the viewer of FIG. 2, or extend axially along the housing 12. Each projection 62 extends to such an extent that end surface of the projection 62 (the left surface in FIG. 2) is in contact with one of the wide surfaces of the mountings 58A, 58B (the right surface in FIG. 2), respectively. The mountings 58A, 58B are fastened to the ends of the projections 62 by bolts 64 to thereby fix the rims 54A, 54B to the engine 60. The housing 12 thus supported by the rims 54A, 54B is fixed to the engine 60. The rims 54A, 54B that extend around the periphery of the motor housing 16 firmly support the housing 12. A part of the housing 12 (the right part of the housing 12 in FIG. 2) is located in the recessed space formed by a surface of the engine 60 and the projections 62. As shown in FIG. 2, the rims 54A, 54B are in contact only at the mountings 58A, 58B thereof with the engine 60. It is to be noted that the engine 60 corresponds to an example of the target of the present invention to which the electric compressor is attached.

A procedure for assembling the tubes 50A, 50B and the rims 54A, 54B to the motor housing 16 will now be described with reference to FIGS. 3 and 4. First, the rims 54A, 54B and the tubes 50A, 50B from which air is removed (that is, the air pressure of the tubes 50A, 50B is below the specified range) are prepared. Next, the tubes 50A, 50B are assembled to the rims 54A, 54B by fitting the projections 56A, 56B of the rims 54A, 54B into grooves 51A, 51B of the tubes 50A, 50B, respectively. Since the tubes 50A, 50B are made of an elastic rubber, the engagement of the grooves 51A, 51B and the projections 56A, 56B prevents the tubes 50A, 50B from being moved off from the rims 54A, 54B by virtue of the friction occurring therebetween. With the engagement, the outer periphery of the tubes 50A, 50B are fixed to the inner periphery of the rims 54A, 54B, respectively, thus the tubes 50A, 50B and the rims 54A, 54B being integrated. In the following description, the tubes 50A, 50B that are fixed to the rims 54A, 54B will also be referred to as tube assemblies 55A, 55B.

Subsequently, the tube assembly 55A is fitted over the periphery of the motor housing 16 by mounting the bottom wall 16B thereof and installed in the groove 16D (see FIG. 4). Then the tube assembly 55B is fitted in the same manner over the periphery of the motor housing 16 by mounting from the discharge housing 20 side and fitted in the groove 16C (see FIG. 4). Air has been removed from the tubes 50A, 50B at the time of assembling the tube assemblies 55A, 55B onto the motor housing 16, the inner diameter of the respective annular tubes 50A, 50B is greater than the outer diameter of the housing 12 (specifically, the outer diameter of the housing 12 measured at positions other than the grooves 16C, 16D). Accordingly, it is easy for the tube assemblies 55A, 55B to be fit over the motor housing 16.

Subsequently, the tubes 50A, 50B are inflated by injecting air through the valves 52A, 52B, respectively. Air is injected until the air pressure of the tubes 50A, 50B reaches a value in the specified range. By so doing, the tubes 50A, 50B are inflated to expand radially inwardly (or toward the housing 12) and to be brought into contact with the surfaces of the grooves 16C, 16D, respectively to be elastically deformed. In other words, the tubes 50A, 50B exerts elastic force acting radially inwardly against the motor housing 16. The tubes 50A, 50B are made of a rubber material. Therefore, the tubes 50A, 50B thus inflated to be in contacted with the respective grooves 16C, 16D, are held in place in the grooves 16C, 16D and the displacement of the tubes 50A, 50B is prevented by virtue of the friction occurring between the tubes 50A, 50B and the grooves 16C, 16D. Thus the tube assemblies 55A, 55B are assembled to the motor housing 16. Because the tubes 50A, 50B and the rims 54A, 54B are thus integrated together into a single structure, respectively, assembly of the tubes 50A, 50B and the rims 54A, 54B to the motor housing 16 can be performed at a time, simplifying the assembling procedure. Subsequently, the mountings 58A, 58B of the rims 54A, 54B are fixed to the engine 60 by bolts 64, with the result that the housing 12 supported by the rims 54A, 54B is fixed to the engine 60. It is to be noted that the tubes 50A, 50B may be inflated after the rims 54A, 54B are fixed to the engine 60.

The operation of the electric compressor 10 will now be described. The motor (30, 34) supplied with electric power from a drive circuit (not shown) dives the rotating shaft 39 with the motor (30, 34). With the rotation of the rotating shaft 39, the movable scroll 24 orbits and the volume of the compression chamber 22A of the compression part 22 varies with the orbiting motion of the movable scroll 24. Refrigerant gas introduced through the suction port 16A flows in the motor housing 16 in the axial direction thereof and then is taken into the compression chamber 22A of the compression part 22. The refrigerant gas is compressed in the compression chamber 22A with the orbiting motion of the movable scroll 24. The compressed refrigerant gas is sent to the discharge chamber 20B and is discharged to the outside of the housing 12 through the discharge port 20A. The air pressure of the tubes 50A, 50B is checked periodically and air is added as appropriate through the valves 52A, 52B. The air pressure of the tubes 50A, 50B is maintained within the specified range so that the desired vibration damping of the 50A, 50B is maintained for a prolonged period of time.

In the electric compressor 10, the tubes 50A, 50B are disposed between the motor housing 16 and the rims 54A, 54B, respectively, so that the motor housing 16 and the rims 54A, 54B are not in contact with each other because of the intervention of the tubes 50A, 50B. The tubes 50A, 50B prevent transmission of vibration of the compression part 22 and the motor (30, 34) to the engine 60 through the rims 54A, 54B and the motor housing 16 (or the housing 12). The tubes 50A, 50B also prevent transmission of vibration of the engine 60 to the housing 12. The tubes 50A, 50B, which are formed hollow and filled with air, prevent heat generation due to the vibration effectively as compared with the solid tubes. Thus, deterioration of the durability of the tubes 50A, 50B against the heat is improved and the desired vibration damping between the housing 12 and the engine 60 is maintained for a long period of time.

In the electric compressor 10, the tubes 50A, 50B, which are formed in a substantially annular shape, may be set correctly in place on the periphery of the motor housing 16. Particularly in the present embodiment, the tubes 50A, 50B which are formed of elastic rubber and fitted around the entire periphery of the motor housing 16 may be prevented from being displaced on the motor housing 16 due to vibration, and the transmission of vibration of the compression part 22 and the motor (30, 34) to the engine 60 through the housing 12 may also be prevented successfully, as compared with the configuration in which the tubes such as 50A, 50B are disposed only partially on the periphery of the motor housing 16.

Furthermore, in the electric compressor 10 in which the tubes 50A, 50B and the rims 54A, 54B are fixed to each other by fitting the projections 56A, 56B of the rims 54A, 54B in the grooves 51A, 51B of the tubes 50A, 50B, respectively, the displacement of the tubes 50A, 50B relative to the rims 54A, 54B may be prevented. Therefore, the position of the tubes 50A, 50B relative to the rims 54A, 54B and the non-contact state between the rims 54A, 54B and the motor housing 16 will not be influenced by any vibration of the rims 54A, 54B transmitted from the engine 60 or by any vibration of the motor housing 16.

First Modification

A first modification of the present invention will now be described with reference to FIG. 5. In the following description of the first modification, only the differences form the first embodiment will be described and the detailed description on the configurations that are common to the first embodiment will be omitted. This also applies to other embodiments and modifications unless otherwise specified. It is to be noted that the internal configuration of the housing 12 is not illustrated in FIG. 5. This also applies to FIGS. 6 and 7, and FIGS. 9 to 14. In the first modification, substantially the same tube assemblies each including a tube and a rim are fitted in the respective grooves 16C, 16D of the motor housing 16. This also applies to other embodiments and modifications which will be described hereinafter.

The first modification of FIG. 5 is different from the first embodiment in the configuration of the tube. Specifically, the first modification differs from the first embodiment in that, unlike the substantially annular-shaped tube 50A, two substantially arc-shaped tubes 150A, 152A are disposed between the rim 54A and the motor housing 16. The tubes 150A, 152A are hollow and the interior of the respective tube 150A, 152A are enclosed and sealed from the exterior thereof. The tubes 150A, 152A are inflated with an appropriate volume of air and the air pressure of the tubes 150A, 152A is maintained in a specified range. The procedure for assembling the tubes 150A, 152A, and the rim 54A to the housing 12 is substantially the same as in the first embodiment.

The configuration according to the first modification exhibits substantially the same effects as the first embodiment. The use of two tubes, namely the tubes 150A, 152A, which are disposed between the motor housing 16 and the rims 54A, 54B, respectively, makes easy the maintenance of the tubes (the rim 54B not being illustrated in FIG. 5). Specifically, each of the tubes 150A, 152A is smaller than the annular-shaped tubes 50A, 50B of the first embodiment, and therefore, when any defect is found in the tubes 150A, 152A, replacement of the tubes 150A, 152A with a new arc-shaped tube can be made easily. In addition, the first modification makes possible replacement of only one of the tubes having a defect, which reduces cost associated with the tube replacement. It is to be noted that the number of the tubes disposed between the motor housing 16 and the rims 54A, 54B is not limited to two, and three or more tubes may be used in one tube assembly.

Second Modification

A second modification of the present invention will now be described with reference to FIGS. 6 to 8. The second modification is different from the first modification in that two sheets 70 are added, i.e. one sheet 70 disposed between the rim 254A and the tube 150A and the other sheet 70 between the rim 254A and the tube 152A. FIG. 6 shows a state in which the air pressure of the tubes 150A, 152A is maintained within the specified range, and FIG. 7 shows a state in which some air is released from the tube 152A, so that the air pressure of the tube 152A falls below the specified range. FIG. 8A is a cross-sectional view of the tube 152A of FIG. 6, and FIG. 8B is a cross-sectional view of the tube 152A of FIG. 7. The cross sections in FIGS. 8A and 8B are taken along a plane that is perpendicular to the extending direction of the tube 152A. As shown in FIG. 6 and FIG. 8A, the sheet 70 that is disposed between the rim 254A and the tube 152A is in contact with both of the rim 254A and the tube 152A. The sheet 70 is formed into a substantially arc shape and made of a rubber, such as EPDM and silicone rubber. The sheet 70 is solid and has a C-shaped cross section. The sheet 70 is disposed extending partially around the outer periphery of the tube 152A. As shown in FIGS. 8A and 8B, the sheet 70 has in the outer periphery thereof three grooves 71 formed extending along the circumference of the respective tubes 150A, 152A (in the direction in which the sheet 70 extends). The rim 254 has in the inner periphery thereof three projections 256A at positions corresponding to the respective grooves 71 of the sheet 70. Each projection 256A is fitted in its corresponding groove 71. As shown in FIG. 8A, when the air pressure of the tube 152A is maintained in the specified range, opposite ends of the sheet 70 in the circumferential direction thereof are not in contact with the peripheral surface of the motor housing 16. It is to be noted that the material of the sheet 70 is not limited to a rubber, and other materials such as the αGEL (registered trademark) may be used. It is to be noted that the sheet 70 corresponds to an example of the auxiliary vibration damper of the present invention. The sheet 70 disposed between the rim 254A and the tube 152A and the sheet 70 disposed between the rim 254A and the tube 150A have substantially the same configuration and are disposed in the same manner.

The following will describe the positional relationship between the tubes 150A, 152A and the motor housing 16 when the air pressure of the tube 150A is maintained in the specified range while the air pressure of the tube 152A is below the specified range, with reference to FIG. 7. When the air pressure of the tubes 150A, 152A is maintained within the specified range, the tubes 150A, 152A exert an elastic force that acts radially inwardly on the motor housing 16 (or acting toward a position O1 which is the axial center of the motor housing 16). As shown in FIG. 7, when some air is released from the tube 152A, the motor housing 16 is pressed toward the tube 152A by the elastic force of the tube 150A, with the result that the motor housing 16 is moved rightward as viewed in FIG. 7. The moving distance of the motor housing 16 increases with a decrease of the air pressure of the tube 152A. When the air pressure of the tube 152A falls below the specified range and the position of the axial center of the motor housing 16 is shifted from O1 to O2, the opposite ends of the sheet 70 disposed on the tube 152A are brought into contact with the outer peripheral surface of the motor housing 16, as shown in FIG. 8B.

In the electric compressor according to the second modification, as the air pressure of the tube 152A lowers with time, the motor housing 16 is moved toward the tube 152A by the elastic force of the tube 150A and the opposite ends of the sheet 70 are brought into contact with the outer peripheral surface of the motor housing 16. The sheet 70 is then in contact with both the rim 254A and the motor housing 16 and prevents transmission of the vibration from the housing 12 to the engine 60 through the rim 254A. In other words, even if the air pressure of the tube 152A is lowered and the vibration damping thereof is lowered accordingly, the sheet 70 auxiliarily continues to prevent transmission of the vibration from the housing 12 to the engine 60. Therefore, transmission of vibration from the housing 12 to the engine 60 is prevented for a prolonged period of time and the reliability of the electric compressor itself is enhanced. In the second modification, the sheet 70 is also disposed on the outer periphery of the tube 150A. When the air pressure of the tube 152A is maintained in the specified range while the air pressure of the tube 150A is below the specified range, the motor housing 16 is moved toward the tube 150A and opposite ends of the sheet 70 on the tube 150A are brought into contact with the outer peripheral surface of the motor housing 16. Thus, transmission of the vibration from the housing 12 to the engine 60 is prevented.

Second Embodiment

A second embodiment of the present invention will now be described with reference to FIG. 9. The second embodiment is different from the first embodiment in the configuration of the rims. Specifically, the rim of the second embodiment is formed by a pair of substantially semi-annular rims 354A, 356A. The rims 354A, 356A have substantially the same shape. The rims 354A, 356A have at upper and lower positions thereof as viewed in FIG. 9 mountings 358A, 360A of a flat plate shape, respectively. A substantially annular-shaped rim is formed by connecting the opposite wider surfaces of the mountings 358A of the rim 354A and their corresponding opposite wider surfaces of the mountings 360A of the rim 356A with each other.

The procedure for assembling the tube 50A and the rims 354A, 356A to the motor housing 16 will be described. The tube 50A from which air is removed beforehand is fitted over the motor housing 16 from the bottom wall 16B thereof and fitted in place in the groove 16C. Then the tube 50A is inflated by injecting air through a valve (not shown) until the air pressure of the tube 50A reaches a value in the specified range. In the second embodiment, the valve is mounted directly to the tube 50A and not exposed to the outside through the rim. Next, the rims 354A, 356A are mounted on the outer periphery of the tube 50A. Specifically, the rims 354A, 356A are mounted such that the rims 354A, 356A surround the motor housing 16. When the air pressure of the tube 50A is within the specified range, the outer diameter of the tube 50A is substantially the same as the diameter of a circle that is formed by the inner periphery of the rims 354A, 356A as seen in the cross section of FIG. 9. With the rims 354A, 356A disposed over the tube 50A, the opposite wider surfaces of the mountings 358A of the rim 354A and their corresponding opposite wider surfaces of the mountings 360A of the rim 356A are brought into contact with each other. In the contacted state, the mountings 358A and the mountings 360A are fixed to the projections 62 of the engine 60 by bolts 64. The rims 354A, 356A are connected with each other over the housing 12. The housing 12 supported by the rims 354A, 356A is thus fixed to the engine 60.

The second embodiment also exhibits substantially the same effects as the first embodiment. In the second embodiment in which the tube 50A is fitted in the groove 16C of the motor housing 16 and then inflated with air before the rims 354A, 356A are attached to the tube 50A, the tube 50A is difficult to be displaced relative to the motor housing 16. Thus, the tube 50A is not displaced easily when the rims 354A, 356A are attached to the tube 50A, which facilitates attaching of the rims 354A, 356A to the tube 50A. If the tube assembly with the tube 50A that is yet to be inflated with air is fitted on the motor housing 16, the tube assembly is not fixed securely to the motor housing 16 at the time when the tube 50A is inflated with air. Therefore, the tube assembly may be displaced from the specified position on the housing 12 while air is injected into the tube 50A. According to the configuration of the second embodiment, however, such displacement of the tube 50A is prevented and the tube 50A and the rims 354A, 356A can be assembled properly to the motor housing 16 at the specified positions thereof. It is to be noted that the number of the rims is not limited to two, and three or more rims may be used.

Third Modification

A third modification of the present invention will now be described with reference to FIG. 10. In the third modification, the tube assemblies 150A, 152A of the first modification are disposed between the motor housing 16 and the rims 354A, 356A of the second embodiment, respectively. The procedure for assembling the tubes 150A, 152A to the motor housing 16 will be described. Firstly, the tubes 150A, 152A are fixed to the inner periphery of the rims 354A, 356A to thereby form tube assemblies 355A, 357A, respectively. Then the tube assemblies 355A, 357A are fitted in the groove 16C of the motor housing 16 such that the tube assemblies 355A, 357A surround the motor housing 16. Secondly, with wider surfaces of the mountings 358A of the tube assembly 355A and the wider surfaces of the mountings 360A of the tube assembly 357A being in contact with each other, the mountings 358A and 360A are fixed together to the projections 62 of the engine 60 by the bolts 64, and then air is injected into the tubes 150A, 152A.

The third modification also exhibits substantially the same effects as the first embodiment. Furthermore, in the third modification, the tube assemblies 355A, 357A can be fitted directly in the groove 16C of the motor housing 16. Specifically, there is no necessity to fit the tube assemblies 355A, 357A over the housing 12 from one end thereof to a specified position on the motor housing 16 (for example, from the bottom wall 16B of the motor housing 16 onto the groove 16C). Therefore, the tube assemblies 355A, 357A may be mounted on the housing 12 irrespective of the contour of the housing 12, which does not lower the freedom of design of the housing 12. In the case that the tube and the rim are integrated in a single part of a substantially annular shape, the maximum outer diameter of the housing 12 between one end of the housing 12 and a specified position at which the tube assembly is fitted cannot be made greater than the inner diameter of the tube assembly, which lowers the freedom of design of the housing 12. However, the above-described configuration of the third modification will not lower the freedom of design of the housing 12.

Third Embodiment

A third embodiment of the present invention will now be described with reference to FIG. 11. The third embodiment is different from the first embodiment in that the tube 50A is disposed between the motor housing 16 and the engine 60. Specifically, the rim 454A is disposed extending over a part of the outer periphery of the tube 50A. The rim 454A has at the top and bottom thereof as viewed in FIG. 11 mountings 458A. The housing 12 is fixed to the engine 60 by fixing the mountings 458A to the projections 62 of the engine 60 by the bolts 64. The remaining part of the outer periphery of the tube 50A that is not covered by the rim 454A is located in a recessed space formed by a surface of the engine 60 and the two projections 62 of the engine 60. In the recessed space, the tube 50A is in surface contact with the engine 60 at a part of inner surfaces of the respective projections 62 facing each other and of the bottom of the recessed space. Contact of the housing 12 with the engine 60 is prevented by the tube 50A interposed therebetween. The procedure for assembling the tube 50A and the rim 454A to the motor housing 16 will be described. The tube 50A is mounted to the inner periphery of the rim 454A to thereby form a tube assembly 455A, and the tube assembly 455A is fitted in the groove 16C of the motor housing 16 by mounting the tube assembly 455A over the motor housing 16 from the bottom wall 16B. Subsequently, the mountings 458A are fixed to the projections 62 of the engine 60 by bolts 64 and the tube 50A is inflated with air. When the air pressure of the tube 50A reaches a value in the specified range, the tube 50A is brought into surface contact with the engine 60 at a part of the inner surfaces of the projections 62 facing each other and the bottom of the recessed space.

The third embodiment also exhibits substantially the same effects as the first embodiment. Furthermore, in the third embodiment in which the tube 50A is brought in contact with the walls of the engine 60, the housing 12 is supported by the walls of the engine 60, as well as the rim 454A. According to the configuration of the third embodiment, the dimension of the rim 454A in the circumferential direction can be reduced and the amount of materials for manufacturing the rim 454A can accordingly be reduced, while the firm support for the housing 12 is maintained.

Fourth Modification

A fourth modification of the present invention will now be described with reference to FIG. 12. In the following description of the fourth modification, only the differences from the third embodiment will be described and the detailed description on the configurations that are common to the third embodiment will be omitted. The fourth modification is different from the third embodiment in the configuration of the tubes. Specifically, in the fourth modification, a substantially arc-shaped tube 450A is disposed between the rim 454A and the motor housing 16 and a substantially arc-shaped tube 452A is disposed between the engine 60 and the motor housing 16. The tube 452A is in surface contact with the engine 60 at a part of the inner surfaces of the respective projections 62 facing each other and the bottom of the recessed space.

The procedure for assembling the tubes 450A, 452A and the rim 454A to the motor housing 16 will be described. The tube 452A from which air is removed beforehand is fitted in the groove 16C of the motor housing 16. Specifically, the tube 452A is set in the right half of the groove 16C of the motor housing 16 as viewed in the axial direction of the housing 12 from the bottom wall 16B side, as shown in FIG. 12 (i.e. the right side in the outer periphery of the motor housing 16 in FIG. 12). Subsequently, the housing 12 on which the tube 452A is mounted is set in the recessed space formed between the two projections 62 of the engine 60. Then the tube 452A is inflated with air. By so doing, the inflated tube 452A is brought into surface contact with the engine 60 at the aforementioned three parts. The tube 450A is fixed to the inner periphery of the rim 454A to thereby form a tube assembly and the tube assembly is fitted in the left part of the groove 16C as viewed in FIG. 12. The mountings 458A of the rim 454A are fixed to the engine 60 by the bolts 64, and the tube 450A is inflated by injecting air thereinto. The fourth modification also exhibits substantially the same effects as the third embodiment. The tube 450A of the fourth embodiment is relatively short in the circumferential direction and therefore can be attached to the rim 454A easily. Furthermore, the tube assembly and the tube 452A are substantially arc shaped and therefore can be fitted directly in the groove 16C, which does not lower the freedom of design of the housing 12. It is to be noted that the number of the tubes disposed between the engine 60 and the motor housing 16 is not limited to one, and two or more tubes may be used.

Fourth Embodiment

A fourth embodiment of the present invention will now be described with reference to FIG. 13. The fourth embodiment is different from the first embodiment in the configuration of the rims. Specifically, in the fourth embodiment, two substantially arc-shaped rims 554A, 556A are disposed on the outer periphery of the annular tube 50A. The rims 554A, 556A are in the same circumference of the tube 50A. The rim 554A is disposed at an upper part of the motor housing 16 and the rim 556A is disposed at a lower part of the motor housing 16 (i.e. the side opposite to the rim 554A across the motor housing 16) as viewed in FIG. 13. In other words, some parts of the outer peripheral surface of the tube 50A of the fourth embodiment are exposed without being covered by the rims. The rims 554A, 556A have mountings 558A, 560A, respectively. The mountings 558A, 560A are fixed to the engine 60 by the bolts 64. Thus, the housing 12 supported by the rims 554A, 556A is fixed to the engine 60.

The procedure for assembling the tube 50A and the rims 554A, 556A will be described. The tube 50A is fixed to the inner peripheries of the rims 554A, 556A, respectively, to thereby form a tube assembly 555A. The tube assembly 555A is fitted onto the motor housing 16 from the bottom wall 16B thereof and is fitted in the groove 16C. The tube 50A is inflated with air and the mountings 558A, 560A are fixed to the engine 60 by the bolts 64. The fourth embodiment also exhibits substantially the same effects as the first embodiment. In the fourth embodiment in which the rims 554A, 556A are disposed on opposite sides of the housing 12, the housing 12 that is held by the rims 554A, 556A from outside is stably supported. It may be so configured that the exposed part of the outer periphery of the tube 50A is in contact with the engine 60.

Fifth Modification

A fifth modification of the present invention will now be described with reference to FIG. 14. In the fifth modification, only the differences from the fourth embodiment will be described and the detailed description on the configurations that are common to the fourth embodiment will be omitted. The fifth modification is different from the fourth embodiment in the configuration of the tube. Specifically, in the fifth modification, a substantially arc-shaped tube 650A is disposed between the rim 554A and the motor housing 16 and a substantially arc-shaped tube 652A is disposed between the rim 556A and the motor housing 16. The tubes 650A, 652A have substantially the same shape and the length of the tubes 650A, 652A in the circumferential direction is substantially the same as the length of the rims 554A, 556A in the circumferential direction. The procedure for assembling the tubes 650A, 652A and the rims 554A, 556A to the motor housing 16 will be described. The tubes 650A, 652A are firstly fixed to the inner periphery of the rims 554A, 556A to thereby form tube assemblies 655A, 657A, respectively. The tube assemblies 655A, 657A are fitted in the groove 16C of the motor housing 16 such that the tube assemblies 655A, 657A hold therebetween the motor housing 16. The tubes 650A, 652A are inflated with air and the mountings 558A, 560A of the rims 554A, 556A are fixed to the engine 60 by the bolts 64. The fifth modification also exhibits substantially the effects as the fourth embodiment. Furthermore, the tube assemblies 655A, 657A which are substantially arc shaped and therefore can be fitted directly in the groove 16C, which does not lower the freedom of design of the housing 12.

Fifth Embodiment

A fifth embodiment of the present invention will now be described with reference to FIG. 15. The fifth embodiment is different from the first embodiment in the cross-sectional shape and the configuration of the tube and the rim. Unlike the tube 50A that is hollow and has a substantially annular cross section, a tube 750A in the fifth embodiment has a substantially C-shaped cross section having an opening 700 that is opened toward the side opposite to the motor housing 16 in the radial direction of the cross section. The opening 700 is formed extending along the entire circumference of the tube 750A. A rim 754A covers the opening 700 so that the entire opening 700 is air-tight and liquid-tight. The tube 750A and the rim 754A form a substantially annular, hollow tube assembly 755A. The interior of the tube assembly 755A is enclosed and sealed from the exterior thereof. The tube assembly 755A is filled with air. Air can be injected into the tube assembly 755A through a valve 752A attached to the rim 754A. The air pressure of the tube assembly 755A can be maintained in the specified range by refilling the tube assembly 755A periodically with air. With the air pressure of the tube assembly 755A kept within the specified range, the motor housing 16 is not in contact with the rim 754A because of the intervention of the tube 750A. The assembling procedure of the tube assembly 755A to the motor housing 16 is substantially the same as the first embodiment. It is to be noted that the tube 750A corresponds to an example of the second vibration damper of the present invention. The fifth embodiment also exhibits substantially the same effects as the first embodiment. Furthermore, the configuration according to the fifth embodiment requires no projection or groove for fixing the tube 750A to the rim 754A. The configuration according to the fifth embodiment facilitates manufacturing of the rims 754A and the tubes 750A.

Although embodiments of the present inventions have been described in detail, these embodiments are mere examples and the electric compressor according to the present invention may variously be modified within the gist of the invention.

For example, the tubes are filled with air in the above embodiments and the modifications. However, the configuration of the tubes is not limited to this.

The tubes may be filled with any medium that provides excellent vibration absorbing characteristics and is less heat-generative under vibration than the material used for the tubes. Vibration absorbing medium to be used in the tubes includes a gas such as nitrogen, a liquid such as ethylene glycol or propylene glycol, a gel, or a resin such as silicone resin.

The tubes 50A,50B may not necessarily have an annular shape, and may have an elliptic shape or a rectangular shape in the cross section as long as the shape conforms to contour of the housing 12. The housing 12 may not necessarily have a cylindrical shape and may have an elliptical and cylindrical shape, for example. Furthermore, the tubes 50A, 50B may not be fitted extending around the circumferential periphery of the housing 12, and extending on the periphery of the motor housing 16 in the axial direction thereof and the opposite longitudinal ends of the housing 12 (i.e. the end of the discharge housing 20 and the bottom wall 16B of the motor housing 16).

The projections 56A, 56B and the grooves 51A, 51B may not necessarily be formed extending around the entire circumference of the outer peripheries of the annular rims 54A, 54B and the tubes 50A 50B, respectively, as long as the rims 54A, 54B are kept from being displaced from the tubes 50A, 50B due to the vibration of the engine 60. The rims 54A, 54B may be fixed to any other components than the engine 60, such as any vehicle frame.

The sheet 70 of the second modification is applicable to the electric compressor in which two or more substantially arc-shaped tubes are fitted in the grooves 16C, 16D of the motor housing 16. Specifically, the sheet 70 may be disposed on the outer periphery of the tubes in the electric compressor according to the third modification (FIG. 10), the fourth modification (FIG. 12), and the fifth modification (FIG. 14). This is also applicable to the tube 452A used in the fourth modification. Additionally, it may be so configured that the sheet 70 is fixed to the outer periphery of the tube by engagement of a plurality of grooves that is formed in one of the sheet 70 and the tube and a plurality of projections that is formed in the other of the sheet 70 and the tube. The sheet 70 may not necessarily be disposed on every tube. For example, the sheet 70 may be used only for the tube that allows air to be released relatively easily or for the tube that tends to deteriorate relatively easily.

In the second embodiment, the tube 50A is fitted over the motor housing 16 and then the rims 354A, 356A are mounted on the tube 50A. However, the assembling order is not limited to this. The procedure for assembling may be such that the wider surfaces of the mountings 358A of the rim 354A and the wider surfaces of the mountings 360A of the rim 356A are brought into contact with each other, a tube assembly formed by fixing the tube 50A from which air is removed beforehand to the inner peripheries of the rims 354A, 356A is mounted on the motor housing 16, the mountings 358A, 360A are fixed to the engine 60 by bolts 64, and then the tube 50A is inflated with air.

Furthermore, in the third modification, the tube assemblies 355A, 357A that are built beforehand are assembled to the motor housing 16. However, the assembling order is not limited to this. For example, the procedure for assembling may be such that the tubes 150A, 152A are fitted in the groove 16C of the motor housing 16 and then inflated with air, the rims 354A, 356A are mounted on the outer peripheries of the tubes 150A, 152A, and the mountings 358A, 360A are fixed to the engine 60 by the bolts 64.

In the fourth embodiment, the tube assembly 555A is built and then assembled to the motor housing 16. However, the assembling order is not limited to this. For example, the procedure for assembling may be such that the tube 50A is set on the motor housing 16 and inflated with air, the rims 554A, 556A are mounted on the periphery of the tube 50A, and the mountings 558A, 560A are fixed to the engine 60 by the bolts 64.

In the fifth embodiment, one tube 750A is disposed between the rim 754A and the motor housing 16. However, the number of the tube 750A is not limited to one, and two or more arc-shaped tubes may be used. In this case, each of the tubes is closed at the opposite ends thereof in the circumferential direction thereof, and the space enclosed by the tubes and the rim 754A is sealed from the exterior thereof.

Specific embodiments of the present invention have been described in detail. However, these embodiments are mere examples and not intended to restrict the scope of the present invention. The embodiments disclosed herein may variously be modified. The technical elements described in the specification and the drawings exhibit the technical significance when used alone or in various combinations, and therefore should not be limited to the combinations disclosed herein. The technique exemplified in the specification and the drawings is to achieve multiple purposes at the same time, and therefore achieving one of the purposes constitutes the technical significance. 

What is claimed is:
 1. An electric compressor comprising: a compression part; a motor that drives the compression part; a cylindrical housing that accommodates therein the compression part and the motor; a supporting member that supports the housing and is configured to be fixed to a target to which the compressor is attached; a first vibration damper that is disposed between the housing and the supporting member; wherein the first vibration damper keeps the housing free from contact with the supporting member and the target, and the first vibration damper has therein a hollow enclosed space.
 2. The electric compressor according to claim 1, wherein the first vibration damper has an annular shape that extends around a periphery of the housing.
 3. The electric compressor according to claim 1, wherein the supporting member has an annular shape that extends around a periphery the housing.
 4. The electric compressor according to claim 3, wherein an inner periphery of the supporting member is configured such that an outer periphery of the first vibration damper is fixed thereon.
 5. The electric compressor according to claim 1, wherein the electric compressor comprises a plurality of the supporting members, and each of the supporting members is non-annular shaped and disposed around the housing.
 6. The electric compressor according to claim 5, wherein inner peripheries of the supporting members are configured such that the outer periphery of the first vibration damper is fixed thereon.
 7. The electric compressor according to claim 2, wherein the first vibration damper is at least at a part thereof in contact with both of the housing and the target, and the first vibration damper keeps the housing free from contact with the target.
 8. The electric compressor according to claim 1, wherein the first vibration damper is disposed between the housing and the target, and the first vibration damper keeps the housing free from contact with the target.
 9. The electric compressor according to claim 1, wherein the first vibration damper is filled with a gas or a liquid, and the first vibration damper is configured such that the gas or the liquid is injectable thereinto.
 10. The electric compressor according to claim 9, wherein the gas is air.
 11. The electric compressor according to claim 1, wherein a recess is formed in one of the outer periphery of the first vibration damper and the inner periphery of the supporting member, a projection is formed in the other of the outer periphery of the first vibration damper and the inner periphery of the supporting member, and the recess and the projection are adapted to be fitted to each other.
 12. The electric compressor according to claim 11, wherein the electric compressor further comprises an auxiliary vibration damper disposed between the first vibration damper and the supporting member, the auxiliary vibration damper is contactable with the housing when the first vibration damper is deformed, and the auxiliary vibration damper keeps the housing free from contact with the supporting member and the target when the first vibration damper is deformed.
 13. The electric compressor according to claim 1, wherein a groove is provided in an outer periphery of the housing, and the first vibration damper is fitted in the groove.
 14. An electric compressor comprising: a compression part; a motor that drives the compression part; a cylindrical housing that accommodates therein the compression part and the motor; a supporting member that supports the housing and is configured to be fixed to a target to which the compressor is attached; and a second vibration damper that extends along an outer periphery of the housing and is disposed between the housing and the supporting member, wherein the second vibration damper keeps the housing free from contact with the supporting member, when the second vibration damper is taken along a plane that is perpendicular to the extending direction of the second vibration damper, the second vibration damper has a C-shaped cross section with an opening that is opened toward a side that is opposite to the housing in the radial direction of the cross section, and the supporting member covers the opening in an air-tight and liquid-tight manner to seal a space enclosed by the supporting member and the second vibration damper. 